With advancements in integrated circuit technologies, the range for applying Bipolar-CMOS-DMOS (BCD), a monolithic technique, has become increasingly wider. With the BCD, the bipolar device, Complementary Metal-Oxide-Semiconductor (CMOS) device, and Double-Diffused Metal-Oxide Semiconductor (DMOS) device can be manufactured on a same chip. The BCD combines the advantages of bipolar devices (large transconductance and high load-driving capability), the advantages of CMOS devices (high degree of integration and low power consumption), and the advantages of DMOS devices (low power consumption and being able to work in switching applications and to transmit large power to the load without expensive packaging and cooling systems). By using BCD, power consumption can be greatly lowered, system performance can be improved, packaging cost for the integrated circuits can be reduced, and better reliability can be achieved.
A double-gate process, i.e., manufacturing the gate regions of at least two types of devices on the same chip at the same time, is one of the most important processes used in BCD. However, the conventional processes of manufacturing double-gate structures often cause device malfunctions, parameter abnormalities and the like.
The disclosed methods and systems are directed to solve one or more problems set forth above and other problems.